Rotary hook-sewing mechanism



B. K. HOHMANN. ROTARY HOOK SEWING MECHANISM.

y APPucATlN minfin/m22, |918. Patented Jan. 4,1921.

R. K. HOHMANN.

ROTARY HOOK SEWING MECHANISM.

APPLlcATxoN FILED MAR. 22. 1918.

Patented Jan. 4,1921.

' nantoz @Het new R. K. HORMANN. ROTARY HOOK SEWING MECHANISM.

APPLICATION Hum MAR. 22. 191s. Patented 4,1521'- a sHEss-SHEET a'.

UNITED STATES I lPATENT OFFICE.

RICHARD K. IICIIMANN, or sIoUX CITY, Iowa, AssIGNoIe. To IICHMANN SEWING MACHINE COMPANY, or PERU, INDIANA. I

-. RQTARY HOOK-SEWING MECHANISM.

To all who-m t may concern Be it known that I, RICHARD K. Hon- -MANN, a citizen of the United States, and

residing at -Sioux City,- VVoodbury county, State of- Iowa, have invented certain new and useful Improvements in Rotary Hook- Sewing Mechanism, of which the following is a specification.

The` present invention relates to stitch forming mechanisms and more particularly to the rotary hook type.

In `my April 8, 1919, a rotary hook sewlng mechanism has been ldisclosed in which the hook rotates toward the operator and means is provided for delivering the bobbin thread on the operators right hand side of the needle. For this purpose the bobbin case has a finger which projects radially outward and over the path of the .hook and terminates at a point at the right hand side of the needle. In the operation ofthe device both limbs of the thread loop are carried along onvthe same side of the finger by the hook. That is to say, the hook during the first portion of its revolution vcarries both limbs of the loop down on the side of the finger toward the hook,'and the loop after being cast around' the bobbin carrier, is drawn up around the finger. Then as the take-up continues to pull the loop into the cloth, the loop is guided and travels along the finger to the bobbin thread, thence along the latter to the fabric. g

According to the present invention, however, the front limb of the loop, immediately after the hook .seizes the -same from the needle, is carried up and over the top lor tip of the finger, so that the front limb is cast across the front surface of the finger at the same time that it is Cast across the front surface of the bobbin casing, the loop being drawn up into the cloth in the usual manner, instead of being formed around the finger as described in my aforesaid application.

The construction of one form of my'inf (vention and the features of novelty will be Specification of Letters Patent.

prior Patent 1,299,468, granted Fig. 2 is a view similar to Fig. l but showing the `parts after the beak has rotated nearly 180.O from the loop seizing position;

y Fig. 3 is a view similar to Figs. 1 and 2 showing the position of the thread loop and parts after the beak has rotated substantially 225 fromvthe loop seizing position;

Fig. 4t' is a view similar to the previous figures illustrating the position of the parts just prior to drawing the loop into the fabric;

- Fig. 5 is a perspective View of the rotary hook;

Fig. 6 is a top plan view of the'rotary hook; p

Fig. 7. is a rear elevation of the rotary hook;

Fig. 8 is a sectional elevation of the rotary hook taken substantially on the line 8`8 of Fig. 5

Fig. 9 is an elevation of the complete device showing the position of the end of the bobbin-thread delivery finger relative to the beak of the rotary hook;

Fig. lO is a side elevation of the race or carrier;

Fig. 11 is a front elevation of the race or carrier; and n Fig. 12 is a top plan view of the race or carrier.

Fig. 13 is a sectional detail taken on the line 13--13 of Fig. 6.

Referring to the. drawings the mechanism shown comprises a loop taker, a carrier or Patented Jan. 4, 1921.

Application filed March 22, 1918. Serial No. 224,001. y

racel mounted therein and a thread or bobbin case carried-by'` the carrier. `g Referring to Figs. 5. to 8 inclusive which show the' loop-f: l taker it will be noted. that it consists of cylindrical ring 20 provided at the rear end .thereof with bosses 21 formed 4with the y apertures such as 26 for the purpose of reducing 'the weight thereof and distributing the same so that-the loop taker will be in dynamic balance. At the front end thereof the ring is formed with a notch 27 extending about half way axially toward the rear end. One of the walls of this notch is inclined as Of course any other I at 28 whereby the meeting of the same with the front edge of the ring forms a pointed beak 29.` This inclined wall 28 is for the purpose of carrying one limb of the thread loop toward the rear of the bobbin casing. As means is provided on the carrier for guiding the said limb the remaining' distance toward the rear of the bobbin casing itis not .necessary to have the inclined wall 28 extend for as great a distance toward the rear of the loop taker as it would be if this wall alone carried the said limb -of the thread loop the entire distance to the rear 'of the bobbin casing. The interior of the ring at the front end thereof is formed Vwith an inwardly extending radial ange 30 which cooperates with the carrier to hold the latter in position in the loop taker. As shown this iiange does not extend entirely around the circumference of the ring but is omitted at the notch 27.l As clearly shown in. Figs. 6 and 9 the point of the beak is located slightly at the left of the plane determined lby the flange 30 and the outer surface of the same is inclined so that at thebase of the beak the` said vsurface is at a greater distance radially from the axis of the ring than the point of the beak. A radial ange 31 extends circumferentially in rear yof the base of the beak for approximately 90o and the pe.

.riphery of this iange smoothly joins the outer surface of the beak at the base thereof. This flange 3l, as shown in Fig. 6, is located slightly at the right of the front end yof the ring and a partial conical wall 32 extends from the front side of the iiange to a Iplane perpendicular to the axis ofthe ring deter' mined by the point of the beak. The outer surface of the-base of the beak and this conical wall smoothly join one another.

A thread delector 33 extends across and over the notch .27 being secured to the ring as by means of the screw 34 at one side of th notch and at the other side of the notch by means such as the screw 35. It will be observed thatthe front edge 36 of this deflector is substantially parallel with the end "of the.

ring but is spaced slightly from said end.

Adjacent the base of the beak the. defiector is formed withV a lug or inwardly extending projection 37 which fits tightlyin a recess formed in the periphery of the flange` 31. Thus it will be apparent that this lug or projection 37 forms a throat between the deflector and beak, this particular structure being described and `claimed in my priorg application 136,688, filed December 13, 1916.

he carrier or race which l prefer to use with the above described loop-taker is illus-' trated in Figs. 10 to 12 inclusive. A carrier of this type is described and claimed in m shown, the carrier or race comprises a casing having a bearlng rim 40 which near the top of the carrier 1s formed with a hook 41 pointing, toward the top and opposite this hook the bearing rim is formed with a nose or hook 42. TheI rearof thev casing consists of a circular wall 43 which is connected to the bearing rim by means of an inclined wall 44. At the center of the rear wall 43' the hook 41 with respect to the axis of the, bearing rim, theI axis of the latter bein at a and the-axis of the pin being at b'. ecause the center ofthe rear wall 43 is eccentric with respectto the bearing rim, it will be observed that the inclination of the connecting wall 44 varies, that is, referring to Fig. 12, the left portion of the inclined wall 44 is more nearly vertical than the right hand portion shown in this figure. This inclined wall 44 is formed with an aperture 46 extending between the hooks 41 and 42 and the rear wall 43 and the edge of this aperture adjacent'the hook 41 is formed so that it constitutes a surface flush and tangent to the hook whereby the limb of the thread loop caught by the vhook 41 will be guided by the said smooth edge to the rear of the carrier. As illustrated in Fig. 9, the bob'- bin casing projects forwardly of the bearing As clearly shown in rim 40 and in order tol guide the front limb i of the thread loop on to the front surface of the bobbin casing, an inclined front wall 47 similar to the rear wall 44 is provided and extends from' the bearing rim to the front of the bobbin casing. It should be noted, however, that this wall is not continuous entirely around the bobbin case but merely extends fromv adjacent hook41 to a point near the bottom'of the bobbin case as shown in Fig. 11. At the top and front of the carrier this wall is constructed to extend vertically upward to form spaced shoulders 48 and 49, this portion being connected to the bearing rim adjacent the hookV 42 by means of a web 50. The shoulders 48 and 49 are provided to loosely receive therebetween alug 51 on a stationary member 52 wherebythe carrier xis prevented from rotating with the loop taker. Just below this lug 51 the front faces of the shoulders are curved toward the left as viewed in Fig. 10 for the purpose of smoothly guiding the thread'to and under said lug. The outer edge of the front inclined wall 47 is not.- joined directlytothe bearing rim 40 but is spaced therefrom thereby forming a groove y f 53. As ex lained in In a lication 136 986 Patent 1,299,468 granted Apri18,1919 AS P y Pr this construction permits the use of a larger bobbin in a carrier of a" given diameter. The forward end of the post 45-isformed with a groove 54 which is adapted to o0- Langerey operate with a latch 55 carried by the bobbin casing to hold the same in position in the carrier. Any other suitable means might be used for retaining the bobbin casing in position Within the carrier. Just at the right of the shoulder 49,' as viewed in Figs. 11 and 12, the Wall 47 is formed with a recess 56 for a purpose presently to be described.

As shown in Figs.' 1 to 4 inclusive and 9, the bobbin casing 57 at the front thereof is provided with an upwardly extending finger 58 which lies in the recess 56 formed in the front wall 47 of the carrier. Thus asthe carrier is held against rotation, the casing' will also be 'held stationary because of the finger engaging in the said recess. As shown, at. its tip, the finger is formed with a short conduit 59 for delivering the bobbin thread. The present invention is illustrated in a rotary hook device' which is adapted to rotate toward the operator and make a plurality of revolutions for eachreciprocation of the needle.- It is therefore necessary to deliver the bobbin thread at the right and in front of the needle, as viewed in Fig. 9, and for this purpose the finger 58 extends' radially outside the pathY of the beak and has its tip positioned at a point to the right of the plane determined by the path of rotation of the point of the beak. Referring to Fig. 9 it will be observed that the conical vall 32 in its rotation passes under the tip of the finger and furthermore that the periphery of the flange 31 on the rotary hook is radially a slight distancefarther from the axis of the hook than the said tip. This particu-v i lar relation of parts, that is to say, the end of the finger, the inclined wall 32, the fiange 31, and the beak constitute an important feature of my invention and is for the purpose of casting the front limb of the thread loop up and over the tip ofthe finger 58. ln the operation of the device the needle loop is seized from the needle by the beak and the front limb of the loop is carried radially outward by the inclined outer surface of the beak so that in coperation with the inclined conical wall 32, the said front limb is cast up and over the tip of the finger 58. The position of the parts and the threads just after this has occurred,' is illustrated in Fig. 1. As the beak continues its rotation say to the position such as illustrated in Fig. 2, the front limb of the loop is guided on to the inclined wall 47 of the carrier and it will be observed that the front surface of the nger smoothly joins this wall 47 so that the front limb of the loop passes freely and Without restriction over the outer surface of both the finger and the Wall 47. The front limb of the loop is cast farther across the front surface of the finger '58 and the front of the bobbin casing as the beak rotates until, when it reaches a position substantlally assho'wn in Fig. 3, the said front limb will have been carried practically all the way across the said finger. The take-up of the sewing machine now becomes operative to' draw up the loop and as shown in Fig. 4the loop passes between the lug 51 on the stationary member '52 and the shoulders 48 and 49.

It will be seen therefore that the needle thread is cast around the bobbin in as direct a path as possible with practically no kinks or unnecessary bends being formed in the same. Furthermore as the front limb of the needle thread loop is cast over the finger 58 and always maintained at the front, the usual twist is not produced with my device, and yet the bobbin thread is delivered at the operators right and in front of the needle as is necessary when the beak rotates toward the operator in order to form atwist stitch and avoid the forming "of a knot stitch.

Although I have described my invention in connection with a particular type of carrier, it is distinctly understood that the invention is not limited to this specific construction as it is obvious that other types of carriers and rotary hooks could have my construction for casting the needle thread over the finger embodied therein, and espe.- cially it is to be understoodl that the invention is not limited to a construction in which the bobbin is mounted eccentrically with respect to the axis'of the circular path of the beak.

Having thus described the invention what is claimed asnew and desired to be secured by Letters Patent is:

1. A rotary hook sewing device including in combination, a rotatable member having a beak, means for delivering the bobbin thread radially outside of the circular path of said beak and means for guiding the front limb of the thread loop up and over the first mentionedmeans immediately after the beak seizes the loop from the needle.

2; A rotary hook sewing device including in combination, a rotatable member having a beak, a finger for delivering the bob.- bin thread radially outside of the circular path of said beak, and means for guiding the front limb of the thread loop up an over the tip of said finger.

3. A rotary hook sewing device including in combination, a member having a beak rotatable toward the operator, means for delivering the bobbin thread radially outside of the circular path of the beak and on the same side of the needle as the beak, and means for guiding the front limb of the needle thread loop up and over the first mentioned means.

4. Arotary hook sewing device including in combination, a beak rotatable toward the operator in a path at the right 0f the needle, a finger for delivering the bobbin thread on the operators right of the needle, and

means for guiding the frontY limb-of the needle thread loop up and over the top of ing a beak, means for delivering the bobbin thread radially outside of the circular path of said beak, and means rotatable with the member for guiding the front limb of the needle thread loop up and over the first mentioned means immediately after the beak seizes the loop from theneedle.

6. A rotary hook sewing device including in combination a rotatable member having a beak, a finger for delivering the lbobbin thread radially outside of the circular path of the beak, said member in rear of the beak having an inclined surface arranged to guide the outer limb of the loop up and over the tip of said finger.

7. A rotary hook comprising a ring having a beak the outer surface of the base of which is radially farther fromv the axis of the hook than the point of the beak and also than the cylindrical surface of the ring.

8. A rotary hookcomprising a ring having a beak the outer surface of the base of which is radially farther Afrom the axis of the hook than the point of the beak, and also than theylindrical surface of the ring, said hook having a partial relatively steep conical Wall in ip ar of the beak, the outer surface of Whichsmoothly joins with the said outer surface of the beak.

9. A rotary hook sewing device including in combination a rotary member having a beak, a stationary carrier, astationary bobbin casing Within the carrier, one of said stationary parts havinga finger at the front thereof extending to a point radially outside the path of the' beak for delivering the bobbin thread, and means for casting one limb ofthe needle thread loop over the tip of saidjinger.

l5 10. A rotary hook sewing device including in combination, a rotary member having a beak, a stationary carrier, a stationary bobbin 'casing Within the carrier, one of said .stationary parts havinga finger at the front 0 thereof extendingto a point radially outside the path of the beak for delivering the bobbin thread, means for .casting one limb of the needle thread loop overthe tip of said finger, and means' for thereafter cast- 5 ing. said limb onto the front surface of'said bobbin casing.

11. A rotary hook sewing device including in combination, a rotary member havlng a beak, a stationary carrier, a stationary bobbin casing Within the carrier, one of said stationary parts having a finger at the front thereof extending to .a point radially'outside the path of the beak for deliverin the bobbin thread,means for casting one imb I of the needle thread loop over the tip of said Laagste casting the front limb of the needle thread I loop over the tip of said finger, and a carrier between the hook and casing having a partial conical Wall in the quadrant ahead of the loop seizing position of the beak, said Wall adapted -to cast said front limb of the -needle thread onto the front surface of the bobbin casing.

13. A rotary hook sewing device including in combination, a rotary hook member having a beak, a stationary bobbin casing having a linger the tip of which is located to deliver the bobbin thread radially outside the path of the beak and .in advanceof the beak When in loop seizlng position,` and means for casting one limb of the needle thread loop over the tip of said linger.

14. A rotary hook sewing device including in combination, a rotary member having a beak, a stationary bobbin casing having a. finger the tip of which is located to .deliver the bobbin thread radially outside the path of the beak and in advance of the beak when in loop seizing position and means on the member forl casting one limb of the needle thread loop over the tip of said finger.

15. A rotaryhook comprising a ring having a beak the point of which is located axially infront of the end of the ring, -and a radial flange on! the periphery of the ring extending circumferentially around the ring from the base of the beak approximately 90 and a conical Wall projecting in front of said flange and terminating substantially in the transverse plane perpendicular to the axis determined by the point of the beak.

16. A rotary hook comprising a ring hav- 'ing a beak at one end thereof, and a radial base of the beak approximately 90o, the periphery of said flange being at a greater distance radially from the'axis of the ring than the point of the beak and smoothly joining the outer surface of the base of the beak.

17. A rotary hook comprising a ring having a beak, the outer surface of the beak be-4 ing smooth from point to base and radially farther from theaxis of theiring at its base than at its point, and a conical wall smoothly joining the base ofthe beak, ex-

tendifng circumferentially in rear of the beak approximately 90. Y

18. A rotary hook comprising a ring having' a beak, the outer surface of the beak being smooth from point to base and radially farther from the axis of the ring at its base mately 90, and a radial flange at the base f of .the conical Wall the radius of which is at least equalto the radius of the outer surface at the base of the beak.

19.l A rotary hook sewing device including in combination, a rotary member having a beak, a linger adapted to deliver the bobbin thread radially outside the path of the beak, said rotary member having* a radial flange on its periphery extending circumferentially partially around the same from the base of the beak and smoothly joining the beak, the radius of said ange being greater than the point of delivery of the bobbin thread, whereby the front limb `of theneedle thread loop is cast onto 'and over said finger immediately after the beak seizes the loop. l

In testimoll whereof I aiix m CHARD HO NN.

si nature. 

